1. Field of the Invention
The present invention generally relates to image rendering technology and, more particularly, to a texture mapping technology for mapping textures to the surface of an object.
2. Description of the Related Art
The image processing performed to display a three dimensional (3-D) image on a two dimensional (2-D) screen comprises geometry process and rendering process. In the geometry process, vertex transformation is performed to vertex coordinates of objects constructing 3-D images. In the rendering process, pixel colors are determined based on the geometry data resulting from the geometry process to create a 2-D image.
In the rendering process, color information for each pixel is computed based on both 2-D coordinate location information and textures, which represents color and pattern of the surface of an object. Then the computed result is written in a frame buffer for display on a screen.
For rendering 3-D images at high speed, it is desirable to address the image data at high speed. The texture mapping needs a large number of addressing operations in order to address texels to be mapped to the surface of objects. However, addressing texels one by one over a certain wide area may increase both the number of instructions and the amount of data communicated from a shader to a texture unit. This may cause a shortage in bandwidth between the shader and the texture unit, resulting in a reduction in processing efficiency.